1,720,994 research outputs found
Functional and coenological changes under different long-term management conditions in Apennine meadows (central Italy)
No full textThe aim of this research was to study the floristic and ecological changes in sub-Mediterranean meadows due to three kinds of management entailing different disturbance intensities. The theoretic framework follows Grime’s theory about the correlation between species richness and disturbance intensities. Phytosociological relevés were carried out in three different management-disturbance situations, namely mowing and grazing, mowing alone, and abandonment. The data from these relevés were processed through statistical analysis, and examined together with ecological parameters (bioindication values and twenty functional plant traits) in order to indicate signifi cant differences within the diversely disturbed meadows. It was found that three identifi ed plant communities corresponded to three different disturbance intensities, and that species richness was comparable between high disturbance situation and those of void disturbance, whilst it considerably decreased under intermediate disturbance. High disturbance condition vs. void disturbance comparison showed the higher differences regarding: species turnover (57% of Sørensen similarity index and 45 differential species), light request and pH soil reaction. Hemicryptophytes, fringe social behaviour type (SBT3), upright forbs, clonal ability, late flowering period emerged as differential traits and species height increases moving to undisturbed situation. Other important evidences concern avoidance strategies which are favoured by mowing and grazing, whereas species equipped with late fl owering period and clonal ability are advantaged under intermediate and void disturbance conditions. Our fi ndings indicated that the species more threatened by abandonment are the accidental ones
Effect of sheep and horse grazing on species and functional composition of sub-Mediterranean grasslands
No full textQuestions: How does horse or sheep grazing affect species richness, diversity and functional composition of plant communities in sub-Mediterranean grasslands? What are the implications of grazing management for species conservation?
Location: Pastures dominated by Bromus erectus grazed by either sheep or horses in the Umbria-Marches Apennines (central Italy).
Methods:We examined grasslands at altitudes ranging from 1000 to 1200 m a. s.l. on north-facing slopes and with a slope angle of 20–40 °. In 20 plots of 1 m2 for each management type, canopy height and above-ground phytomass were recorded. In 120 plots (60 for eachmanagement type) of 1 m2 the cover value of each species was recorded. Floristic diversity and community similarity of the sheep- and horse-grazed conditions were compared. Functional plant traits and strategies or ecological requirements were also evaluated.
Results: The sward was shorter and supported less above-ground phytomass in the horse-grazed area. The sheep- and horse-grazed areas had similar floristic diversity. Accidental species were the species most affected. Plants with lownutrient
requirement spread in horse-grazed pasture. Functional traits of species were filtered by the system, resulting in diverse cover values of species. Horse grazing promoted plants with a robust defence strategy (avoidance and tolerance) that ensured leaves were replaced when horses were not grazing, as well as species with clonal growth. In the sheep-grazed area, a higher level of selective defoliation and a delayed start to the grazing period promoted species with low palatability, a late-flowering strategy and those intolerant to trampling by large herbivores (chamaephytes). The value of forage feed was slightly higher in
horse-grazed pasture. Grazing of horses was more effective than that of sheep for controlling dominant unpalatable tall grasses.
Conclusion: In terms of biodiversity conservation, horse grazingmay be considered as useful as sheep grazing, but only if managed at optimal stocking rates, because the increase in short grasses and annuals (growth forms with poor root systems) does not ensuremaintenance of soil on steep slopes
Biodiversity conservation: geosynphytosociology as a tool of analysis and modelling of grassland systems
No full textThe study site is located along the Umbria-Marches Apennine (central Italy). Following a series of research
topics, the aims and objectives of this paper are to present the tested process of forage resources modelling
at a large scale in a pastoral system in order to define essential management and decision making aimed on
biodiversity conservation.
The analytical process is based on correlation between phytosociological and agro-zootechnical analysis. This
approach allows one to extend any type of heterogeneous data, provided this is in any way correlated to the
intrinsic characteristics of the plant community, can be interpolated to the whole polygon and therefore to
all polygons referring to the same phytosociological unit. In terms of planning and application, the results of
phytosociological modelling are much more useful when integrated in a database (GIS), in which the different
information levels, based on hierarchical criteria, are simulated in multiple polygon segmentations.
In particular, this method allows one to obtain a first general overview of the forage resource using the theoretical
data linked to the phytosociological interpretation of the territory. Subsequently, this overview can be enhanced
with actual quantitative data, offering also a qualitative dimension coming from the phytosociological aspects.
Key words: Geosynphytosociological modelling, plant community, forage resource, carrying capacity, grazing
management, biodiversity conservation
Contributo alla quantificazione della fitomassa epigea di alcuni pascoli dell’Appennino umbro-marchigiano (Italia centrale)
Full text linkIl presente studio rappresenta un primo approccio alla descrizione, in termini quantitativi, della risorsa foraggera ovvero della produttività che caratterizza alcune tipologie di pascolo nell’Appennino Umbro-Marchigiano. Seppur ancora perfettibili i risultati ottenuti sono coerenti con l’ipotesi di base e cioè con la constatazione che la produttività aumenta passando dalle
comunità xeriche a quelle semimesofile ed ai prati-pascolo. La produttività dipende infatti, da diverse variabili quali: disponibilità di risorse ambientali, intensità con cui le diverse componenti
delle piante vengono consumate dagli erbivori (GRIME, 2001), composizione floristica del pascolo (le specie vegetali
influenzano la fisionomia e la struttura architettonica del manto erboso e quindi la produzione), caratteristiche geomorfologiche,
pedologiche e climatiche del sito di studio, ecc
Trait-related flowering patterns in submediterranean mountain meadows
No full textThe research aims were to identify the flowering pattern and the related functional strategies in submediterranean mountain meadows (central Italy) and understand their relationships with some environmental and community structure variables. The number of flowering shoots per species was counted and environmental data were collected in 40 plots during 2009. Analysis of the species and trait data sets highlighted a flowering pattern and an underlying functional pattern. Dominant species tend to bloom in the central phases of the growing season
when no stress acts in the system and a long time is
available for plant growth and seed maturation. This kind of species does not need functional strategies allowing the canopy fast pre-emption or the tolerance to drought stress. Non-dominant species have two groups of functional strategies that allow them to share the same flowering period of dominant ones by a
different type of space occupation (spatial niche partitioning) or to flower before or after their flowering period (temporal niche partitioning). The functional strategies involved in the temporal niche partitioning have a dual ecological meaning, limiting competition with dominant species by fast growth and seed
maturation (e.g., short stature, mobilisation of stored reserves, colonization of unexploited soil niches by clonal growth organs and light seeds) and enabling tolerance to drought stress (e.g., scleromorphic and succulent leaves, persistent green leaves, tap roots) and to the low light availability at the ground level
owing to the change of grassland structure (e.g., tall size and upright growth form)
Functional differentiation of central Apennine grasslands under mowing and grazing disturbance regimes
Full text linkThis research dealt to two grasslands potentially developing the same vegetation type because sited in the same environmental contest (bioclimate, substratum, soil, slope, altitude) but under diverse management regimes (grazing and mowing) for many decades. The evidenced differentiation between the two pastoral vegetations can be attributed to disturbance type and the statistical functional analysis performed through seven plant traits (prostrate form, early
flowering, storage organs, clonal ability, basal meristems, chemical defences and hairs), revealed the distinguishing patterns. Discriminant analysis pointed out typical biological
attributes for each disturbance conditions, while from correlation analysis emerged different possible traits combinations which do not follow the previous traits separation. Such outcomes are explainable because both grazing and mowing provoke aboveground phytomass removal, although grazing is a selective pressure, while mowing gives to all the species the same development
chances. It is reasonable to conclude that convergent strategies within the two systems are possible and frequent
Il management degli allevamenti di montagna come strumento di conservazione delle praterie e di sviluppo dell’azienda zootecnica (L’uomo e l’ambiente; 51)
No full textL'uomo e l'ambient
Effect of spatial and temporal patterns of stress and disturbance intensities in a sub-Mediterranean grassland
No full textThe present study examined a sub-Mediterranean pastoral system in the central Apennines (Italy) with a long history of
grazing, where winter cold stress is alternated with summer drought stress. The research goals were to ascertain whether
different floristic structures correspond to different stress conditions (xeric and semimesic), and whether peculiar functional
plant traits (such as avoidance and tolerance mechanisms) respond to stress/disturbance intensities, and understand how
vegetation reacts to changeable livestock pressure (through floristic and plant trait variations). Cluster analysis indicated that
separate communities develop under different stress intensities. Other analyses highlighted how avoidance strategies predominate within the pastoral system. Observations of grazed and ungrazed patches conducted in 10-m transects revealed spiny cushion formation in semimesic grassland, where a brief period of overgrazing occurs in late summer, causing variations in plant community structure. All these results confirm the importance of historical grazing and current land use, showing how small disturbances and stress variations cause ecosystem responses. Best practices for management were identified. In xeric conditions, it is advisable that the intensity of disturbance be lessened, while in semimesic grassland overgrazing should be forbidden during the dry period, because it could facilitate the development of spiny patches, and subsequent spread of Brachypodium rupestre
Effects of grazing vs mowing on the functional diversity of sub-Mediterranean productive grasslands
No full textQuestions: In order to preserve the ecosystem functioning of semi-natural
sub-Mediterranean calcareous grasslands of the Central Apennines, it is vital to
understand how functional diversity (FD) changes in relation to different types
of disturbance. To compare the effects of sheep grazing and those of late-summer
mowing, we asked: do different types of disturbance (grazing and mowing)
affect FD; are FD and species diversity positively correlated in both grazed and
mown grasslands; do FD and species diversity take different paths in the two
disturbance regimes; and are different FD values related to changes in the composition
of traits linked to competitive ability, resource acquisition and resistance
strategies?
Location: Grazed andmown sites in the Central Apennines (Italy).
Methods: We performed redundancy analysis and indicator species analysis to
characterize the trait composition of the two disturbance regimes. We calculated
FD for each selected trait and a compound FD for multiple traits, using Rao’s
quadratic entropy index. Differences in FD between disturbance regimes were
tested with a nested ANOVA. We performed a regression analysis between FD
and species diversity indices under the two disturbance types.
Results: Species and functional diversity were positively correlated in both disturbance
types. FD was generally less correlated with species diversity variations
in mown grasslands than in grazed ones, suggesting that late mowing
leads to higher levels of functional redundancy (i.e. to a wider overlap of species
functional composition). Late mowing promoted higher species and functional
diversities and a wider variety of functional traits in the plant
community. Grazing, besides negatively affecting the species diversity of grasslands,
reduced their FD by favouring the dominance of traits related to avoidance
and tolerance strategies.
Conclusion: The continuation of late mowing is recommended to preserve the
richness and variability of functional groups and the ecosystem functioning of
sub-Mediterranean grasslands
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